The applicant, Janis C. Weeks, is an associate professor (without tenure) at the Institute of Neuroscience at the University of Oregon. Her long- term career goals are to understand how hormonal effects on the structure and synaptic connectivity of identified neurons lead to changes in behavior. During metamorphosis of the moth, Manduca sexta, ecdysteroid hormones control metamorphic events in the nervous system including programmed neuron death, and the growth and regression of neuronal arbors. These morphological changes form a substrate for the massive behavioral changes that accompany the transitions between life stages. The proposed experiments address several issues related to how ecdysteroid-induced regression and/or growth of the dendritic arbors of identified motoneurons during metamorphosis affects their behaviorally-relevant synaptic inputs from identified sensory neurons and interneurons. Electrophysiological and anatomical (light and electron microscopic) techniques will be used. In addition, inhibitors of DNA, RNA, and protein synthesis will be tested for their ability to block the ecdysteroid-triggered dendritic regression, and programmed death, of identified motoneurons. This research program is in a rapidly expanding phase, and several of the projects are beginning to require a great deal of direction. It is essential, therefore, that Dr. Weeks spend as much time as possible in the laboratory, both to carry out experiments and to guide the research of her graduate student and postdoctoral collaborators. Dr. Weeks now carries a burdensome teaching load of undergraduate and graduate courses that detracts significantly from her time spent on research. If awarded an RCDA grant, she would be relieved of all teaching responsibilities at the University of Oregon except a yearly graduate course in her research area, and of all committee and administrative duties. This would allow her to spend essentially fulltime on research activities. In addition, some of the extra research time provided by an RCDA award would be used to initiate pilot studies in collaboration with Dr. Richard B. Levine at the University of Arizona, to test the feasibility of addressing some questions of hormone action on identified Manduca neurons in cell culture. These studies would not otherwise be undertaken. In summary, an RCDA award would significantly enhance the applicant's development as an independent researcher by allowing her to devote essentially full-time to her expanding research program during a critical phase of her career. Furthermore, the opportunity would be provided to pursue a potentially very powerful new research direction.